Unwanted text duplication with sortableJS

Hello,
I want to create a block in which the elements are sortable.
The problem is that when I sort the elements with sortableJS, their content is duplicated and added after my block.
Here is a video to explain :

https://github.com/codex-team/editor.js/assets/16758858/9acd028b-7dfa-4d16-87a9-d632dc400c0f

And a Codepen link that reproduces the problem :
https://codepen.io/raphaelriehl/pen/QWoxqaE

The purpose of this plugin is to create a photo gallery with the possibility of reordering photos.

How to solve this problem ?